import java.util.Scanner;
class ATM {
    public static void main(String[] args){

        Scanner scn = new Scanner(System.in);

        double banlance = 0;

        while(true){
            System.out.println("======ATM======");
            System.out.println("1、 存款");
            System.out.println("2、取款=");
            System.out.println("3 显示余额");
            System.out.println("4、退出");
            System.out.println("请选择(1-4)：");



            int res = scn.nextInt();

            System.out.println("您选择的是----》" + res);
            if(res ==1){
                System.out.println("请输入存款金额");
                double price = scn.nextDouble();
                banlance = banlance + price;

            }else if (res == 2){
                System.out.println("请输入取款金额");
                double price2 = scn.nextDouble();

                if(price2 > banlance){
                    System.out.println("当前余额为:"+banlance +"-------余额不足");

                }else if(price2 < 0){
                    System.out.println("取款金额不合法");

                }else{
                    banlance = banlance - price2;

                }



            }else if(res == 3){
                System.out.println("当前余额为:"+banlance);

            }else if(res == 4){

                break;

            }

        }

    }

}